Comment 7 for bug 2006484

Reviewed: https://review.opendev.org/c/openstack/charm-rabbitmq-server/+/876921
Committed: https://opendev.org/openstack/charm-rabbitmq-server/commit/e381a20f1d5238caf567ac66c13b3a943ecc654d
Submitter: "Zuul (22348)"
Branch: stable/jammy

commit e381a20f1d5238caf567ac66c13b3a943ecc654d
Author: Alex Kavanagh <email address hidden>
Date: Wed Feb 22 14:56:27 2023 +0000

    Fix focal to jammy series upgrade

    This is a fix/workaround to the package upgrade bug that affects the
    charm. The post-inst package script updates the .erlang.cookie if it is
    insecure during the upgrade of rabbit from 3.8 to 3.9. This breaks the
    series-upgrade resulting in a charm erroring on the post-series-upgrade
    hook.

    This fix works by checking if the .erlang.cookie has changed during the
    post-series-upgrade hook and either updating the cookie in peer storage
    (if it is insecure) or ensuring that the cookie from peer storage is
    written to the .erlang.cookie if it isn't the leader. This ensures that
    the cluster continues to work and that the series-upgrade can be
    completed across the cluster.

    Change-Id: I540ea8da85b3b4326ccb8194f1d8b1050b04eae9
    Closes-Bug: #2006484
    (cherry picked from commit 55b985f55ca4eb2b2a7229c8dcc70abc8c8940f4)